JP2002131625A - Range-finding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hybrid type range-finding device capable of performing accurate range-finding by correcting offset caused in each of sensors constituting a photodetector when performing active mode integration without using a large- capacity non-volatile memory. SOLUTION: This range-finding device is equipped with a light projecting means for projecting light for range-finding to an object, a light receiving means consisting of multiple sensors receiving reflected signal light being the light for range-finding from the object, and a storage means for storing output data from the multiple sensors in a state where the light for range-finding is not projected. The output data from the multiple sensors of the light receiving means in a state where the light for range-finding is projected is corrected based on the output data from the multiple sensors of the light receiving means in the state where the light for range-finding is not projected and stored in the storage means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a distance measuring apparatus, and more particularly, to projecting a signal light from a light projecting means toward a subject, and removing a steady light component from the subject by a steady light removing means. The active integration mode integration is implemented in a hybrid type distance measuring device that can execute two integration modes, active mode integration that integrates only the signal light component from the camera and passive mode integration that integrates the steady light component from the subject. The present invention relates to a distance measuring device that corrects an offset generated in each sensor constituting a light receiving element due to a fixed pattern noise or the like when the measurement is performed.

[0002]

2. Description of the Related Art In a distance measuring apparatus for performing passive AF conventionally used in a camera, there is a problem that an offset generated in each sensor constituting a light receiving element due to a dark current deteriorates distance measuring performance.

Therefore, offset data for each sensor constituting the light receiving element is stored in a non-volatile memory or the like at the time of manufacture, as disclosed in Japanese Patent Application Laid-Open No. Hei 3-10473. There is known a technique for performing offset correction based on data.

[0004]

However, in the case of the method disclosed in Japanese Patent Laid-Open Publication No. Hei 3-10473, since the offset data must be stored in a nonvolatile memory in advance, a huge memory capacity is required. However, there is a problem that the cost is increased and the mounting area of the memory is increased.

In the hybrid type distance measuring apparatus, when performing the active mode integration, an offset is also generated due to fixed pattern noise due to switching in the integration circuit at the time of steady light removal operation. Since the magnitude of the offset is related to the number of switching operations, it is necessary to consider the number of switching operations accompanying the steady light removal operation when performing offset correction.

SUMMARY OF THE INVENTION It is an object of the present invention to correct an offset generated in each sensor constituting a light receiving element when active mode integration is performed without using a large-capacity nonvolatile memory in a hybrid type distance measuring apparatus. It is another object of the present invention to provide a distance measuring device capable of performing highly accurate distance measuring.

[0007]

According to the present invention, there is provided, in order to solve the above-mentioned problems, (1) a light projecting means for projecting distance measuring light to a subject, and a reflection of the distance measuring light from the subject. Light receiving means comprising a plurality of sensors for receiving the signal light, and storage means for storing output data from the plurality of sensors of the light receiving means in a non-light emitting state of the distance measuring light, wherein the storage means Based on the stored output data from the plurality of sensors of the light receiving unit in the non-projecting state of the distance measuring light, the output data from the plurality of sensors of the light receiving unit in the projecting state of the distance measuring light. Is provided.

According to the present invention, in order to solve the above-mentioned problems, there are provided (2) an integral control means for performing integral control on a plurality of sensors of the light receiving means, and a constant incidence on the plurality of sensors of the light receiving means. Stationary light removing means for removing a light component to be read, reading means for reading object image data output from a plurality of sensors of the light receiving means, and subject distance based on the subject image data read by the reading means. Calculating means for calculating data corresponding to the distance, projecting the distance-measuring light from the light projecting means toward the subject, and calculating the steady light component from the subject by the steady light removing means. An active mode integration in which the integration control means performs a plurality of times of an integration operation of removing only the light components for distance measurement from the subject by the integration control means; The distance measuring apparatus according to (1), which is capable of executing two integration modes, namely, a passive mode integration for integrating a stationary light component from an object, is provided.

According to the present invention, in order to solve the above-mentioned problems, (3) when the active mode integration is performed by the integration control means in the non-light emitting state of the distance measuring light, The subject image data output from the plurality of sensors of the light receiving unit when the integration control unit performs active mode integration in the projection state of the distance measuring light according to the subject image data output from the plurality of sensors. The distance measuring apparatus according to (2), wherein the distance is corrected.

According to the present invention, in order to solve the above-mentioned problems, (4) in the projection state of the distance measuring light,
The number of repetitions of the active mode integration operation when performing the active mode integration by the integration control means,
By the same number of times, in the non-projection state of the distance measuring light, the distance measuring light is obtained by subject image data from a plurality of sensors of the light receiving means obtained by performing an active mode integration operation by the integration control means. The distance measuring apparatus according to (2), wherein subject image data obtained from the plurality of sensors of the light receiving means obtained in the light emitting state is corrected.

According to the present invention, in order to solve the above-mentioned problems, (5) in the projection state of the distance measuring light,
In the non-light projection state of the distance measuring light, the integration mode control unit performs the active mode integration in a time shorter than one integration time during the active mode integration operation when the integration mode control unit performs the active mode integration. Correcting subject image data from the plurality of sensors of the light receiving unit obtained in the projection state of the distance measuring light, based on subject image data from the plurality of sensors of the light receiving unit obtained by performing an operation. Features (2)
Is provided.

According to the present invention, in order to solve the above-mentioned problems, (6) in the projection state of the distance measuring light,
In the non-light projection state of the distance measuring light, the sensitivity is lower than the sensitivity of the plurality of sensors of the light receiving unit during the active mode integration operation when the active mode integration is performed by the integration control unit. By subject image data from a plurality of sensors of the light receiving means obtained by performing an active mode integration operation by
The distance measuring apparatus according to (2), wherein subject image data obtained from a plurality of sensors of the light receiving means obtained in a state where the distance measuring light is projected is corrected.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment) FIG. 1 is a block diagram of a main part showing a configuration of a camera distance measuring apparatus according to a first embodiment of the present invention.

In FIG. 1, reference numeral 107 denotes a pair of line sensors 102a and 102 for distance measurement toward a subject.
Reference numeral 101a, 101b denotes a light receiving lens for forming a pair of subject images on a pair of line sensors 102a, 102b.

Here, a pair of line sensors 102a, 102a
Numeral 02b converts a pair of subject images formed by the light receiving lenses 101a and 101b into an electric signal according to the light intensity.

In FIG. 1, reference numeral 103 denotes
An integration control circuit as integration control means for controlling the integration operation of the pair of line sensors 102a and 102b. Reference numeral 106 denotes a pair of light components which are constantly incident on the pair of line sensors 102a and 102b. This is a stationary light removing circuit as a stationary light removing unit that removes the photocurrent output from the line sensors 102a and 102b.

In FIG. 1, reference numeral 105 is
It is a CPU that outputs various control signals, inputs various data, calculates distance measurement, and the like.

That is, the CPU 105 controls the pair of line sensors 102 through the integration control circuit 103.
a, which functions as a reading means for reading the subject image data output from the a and 102b, and also functions as a calculating means for calculating data corresponding to the subject distance based on the subject image data read by the reading means. It is.

The CPU 105 further has a function of controlling the light projecting means 107, emits signal light from the light projecting means 107 toward an object, and outputs a signal light to the stationary light removing means. An active mode integration in which a light removal circuit 106 removes a steady light component from a subject and the integration control circuit 103 repeats an integration operation of integrating only a signal light component from the subject a plurality of times; The camera has a function of controlling the overall operation of the range finder of the camera capable of executing two integration modes, namely, passive mode integration for integrating the stationary light component.

In FIG. 1, reference numeral 104 denotes
An A / D conversion circuit is provided between the integration control circuit 103 and the CPU 105 and reads an object image signal from the integration control circuit 103 and performs analog / digital (A / D) conversion.

That is, in the first embodiment, in the distance measuring apparatus having the configuration shown in FIG. 1, active mode integration for removing the stationary light component and integrating the signal light component is performed while projecting the signal light. After reading the sensor data by the integration, the active mode integration is performed without projecting the signal light, and the sensor data by the integration is read as the offset generated during the active mode integration.

Then, the sensor data when the signal light is not projected (see FIG. 5 (b)) is subtracted from the sensor data when the signal light is projected (see FIG. 5 (a)). (C) is used as sensor data, and a distance measurement calculation is performed using this data.

According to such a first embodiment, E
Without increasing the capacity of a non-volatile memory such as an EPROM (not shown), offset of sensor data due to fixed pattern noise or the like can be removed, and highly accurate distance measurement can be performed.

FIG. 2 is a diagram illustrating a specific configuration of the stationary light removing circuit 106.

In the configuration of the stationary light removing circuit 106 shown in FIG. 2, reference numeral 110 denotes a photodiode, one end of which is connected to a power supply, and the other end for detecting an optical signal is connected to the source of the transfer transistor 111. Have been.

The drain of the transfer transistor 111 is connected to the ground, and the gate is connected to the output of the inverting amplifier 112 via a switch SW1 composed of a switching transistor or the like.

A current storage capacitor C1 is connected between the source and the gate of the transfer transistor 111, and the source and the photodiode 11 are connected to each other.
The connection point of 0 is connected to the input of the inverting amplifier 112.

This inverting amplifier 112 is a CMO composed of a p-type MOS transistor and an n-type MOS transistor.
An S configuration inverting amplifier may be used.

Between the input and output of the inverting amplifier 112, there is provided a capacitive element C2 for performing feedback for detecting a photocurrent, a switching transistor for resetting the electric charge accumulated in the capacitive element C2, and the like. Switch SW
2 are connected.

A capacitively coupled inverting amplifier circuit is provided at a stage subsequent to the above configuration. The inverting amplifier circuit includes a capacitive element C3 having one end connected to the output of the inverting amplifier 112,
Inverting amplifier 1 to which the other end of this capacitive element C3 is connected
13 and a capacitive element C4 provided between the input and output thereof and a switch SW3 composed of a switching transistor and the like connected in parallel to the capacitive element C4.

The output VS2 of the inverting amplifier circuit has a phase inverted with respect to the signal of the input VS1 and a gain (C3 / C3 / C4) determined by the capacitance of the capacitive elements C3 and C4.
The signal amplified in C4) is output.

FIG. 3 is a timing chart showing a basic operation of the stationary light removing circuit 106.

A switch SW as shown in FIG.
As can be seen from the timing of 2, the steady light removing circuit 106 resets the switch SW2 twice for one light projection and performs two integration operations.

The first time, the light emitting means 107 is in the non-light emitting state, and the second time, the light emitting means 107 is in the light emitting state, so that the difference between the two can be detected.

Then, as shown in FIG. 3A, a period T1 is a period for storing the steady light. The switch SW1 is turned on, the switch SW2 is turned off, and the photodiode 110 is turned on.
The photocurrent I _PD generated in the transfer transistor 111
The feedback is applied to the gate voltage of the transfer transistor 111 via the inverting amplifier 112 so that the gate voltage flows to the ground via.

As a result, the voltage between the source and the gate of the transfer transistor 111 becomes a voltage value corresponding to the photocurrent I _PD , and this voltage value is held by the capacitive element C1, whereby the photocurrent I _PD corresponding to the steady light is obtained. Is discharged.

Here, when the switch SW1 is turned off,
If the amount of charge held in the capacitive element C1 changes due to the feed-through charge and an error of ΔI _PD occurs in the current flowing through the transfer transistor 111, the error component Δ
I _PD flows to the feedback system of inverting amplifier 112.

Therefore, after the switch SW2 is turned on in the period T2 to reset the capacitive element C2, the error component ΔI _PD is integrated in the period T3.

Next, after the switch SW2 is turned on again in the period T4 to reset the capacitive element C2, the signal light is projected from the light projecting means 107 in the period T5, and the error component ΔI _PD and the light component are added by the light projection. The signal light component I _PDS is integrated.

By making the integration times of the periods T3 and T5 the same and taking the difference between the integration values, the signal light component I _PDS
Can be detected.

Regarding this difference, the capacitance elements C3, C3
4. The capacitively coupled inverting amplifier constituted by the switch SW3 and the inverting amplifier 113 may be operated as follows.

First, as shown in FIG.
3 until the end of the integration of the error current component ΔI _PD of the switch SW
3 is turned on, and the switch SW3 is turned off immediately before the switch SW2 is turned on in the period T4.

As a result, as shown in FIGS. 3E and 3F, the switch SW3 is changed from ON to OFF in the output VS2 of the capacitively coupled inverting amplifier composed of the inverting amplifier 113. With reference to the voltage of the input VS1 at the time, a change in the voltage of the input VS1 thereafter appears.

Therefore, as shown in FIG. 3D, the output of VS2 at the end of the integration of the period T5 includes the output voltage of VS1 at the end of the first integration of the period T3 and the output voltage of the VS2 at the end of the integration of the period T5. The voltage corresponding to the difference voltage from VS1 at the end of the integration, that is, the component of the error current component ΔI _PD is removed, and the signal light current component I _PDS generated by the light projection is given by I _PDS × (t / C2) × (C3 / C4) (t is a light projection time).

As described above, the transfer transistor 111
Even if the current discharged by the above has an error with respect to the stationary light current, only the signal light component can be detected by the configuration of the stationary light removing circuit 106 as shown in FIG.

FIG. 4 shows an integration control circuit 103, an A / D conversion circuit 104 and a CPU 105 according to the first embodiment.
5 is a timing chart showing a sequence of integration and sensor data readout according to the first embodiment.

That is, FIG. 4A shows an integration start control signal RESET, and integration starts when L → H.

FIG. 4B shows an integration stop control signal EXTEND, and integration stops when H → L.

FIG. 4C shows the active mode integration control signal INTCLK. The period between the first pulse, the second pulse, and the third pulse is set to T3 in FIG.
The period between the pulse and the fourth pulse corresponds to T5 in FIG. 3, respectively, and thereafter is repeated.

FIG. 4D shows the signal light projection in which the signal light is projected during the H period.

FIG. 4E shows a sensor data read control signal RWCLK, which outputs integrated data of each photodiode for each pulse.

FIG. 4F shows the integrated data output MDATA of the monitor sensor.

The monitor sensor is, for example, a sensor having the highest integration speed among the photodiodes constituting the line sensors 102a and 102b.

In FIG. 4, t1 is an active mode integration period with light emission, and integration operations of 1 to n cycles are performed until the MDATA output reaches a predetermined level.

Further, t2 is a sensor data reading period in active mode integration with light projection.

Further, t3 is an active mode integration period without light emission, in which the integration operation of n cycles performed in active mode integration with light emission is performed without light emission.

Further, t4 is a sensor data reading period in active mode integration without light projection.

FIG. 5 is a diagram showing sensor data in each active mode integration, as described above.

That is, FIG. 5A shows sensor data in active mode integration with light projection, and FIG.
5B shows sensor data in active mode integration without light projection, and FIG. 5C shows sensor data in active mode integration with light projection and sensor data in active mode integration without light projection. The sensor data after correction using the data is shown.

FIG. 6 is a flowchart showing a procedure of a distance measuring sequence according to the first embodiment.

First, in step S101, pre-ranging is performed in the active mode or the passive mode, and a ranging method is selected based on the result.

At this time, the distance measuring method may be selected by judging the luminance using the photometric data or the like.

Next, in step S102, step S
If the selection result at step 101 is the active mode, the process proceeds to step S103; if the result is the passive mode, the process proceeds to step S103.
Proceed to 110.

Next, in step S103, an integration mode, a monitor range, a sensor sensitivity, an integration end condition, and the like are set.

Next, in step S104, the light emitting means 1
The active mode integration is performed while projecting the signal light from 07.

A / D conversion is performed by the A / D conversion circuit 104 to read out sensor data.
Store data in M.

Next, in step S106, step S
The integration conditions are set in the same manner as 103.

Next, in step S107, the active mode integration is performed for the same number of cycles as the number of light projections in the integration in step S104 without projecting the signal light.

Next, in step S108, step S
CPU 105 reads out sensor data in the same manner as
The data is stored in the RAM inside.

Next, in step S109, step S
Offset correction is performed based on the sensor data read at 108.

This offset correction is performed in step S108
May be performed each time one data is read during the reading of the sensor data.

Next, in step S110, step S110
The integration conditions are set in the same manner as 103.

Next, in step S111, passive mode integration is performed.

Next, in step S112, step S
CPU 105 reads out sensor data in the same manner as
The data is stored in the RAM inside.

Next, in step S113, distance measurement data is calculated by a known correlation operation, interpolation operation, or the like.

FIG. 7 is a flowchart showing a procedure of offset correction according to the first embodiment.

First, in step S121, the number of sensor data to be subjected to offset correction is set.

Next, in step S122, the head data of the data to be subjected to offset correction is set with the sensor data at the time of integration with light projection.

Next, in step S123, head data of data used for offset correction is set in sensor data at the time of integration without light projection.

Next, in step S124, the offset is calculated by taking the difference between the reference data and the sensor data at the time of integration without light projection.

Here, the MAX value of the 8-bit A / D 2
Although 55 is used as the reference data, a reference voltage level or the like at the time of integration may be used as the reference data.

Next, in step S125, the offset calculated in step S124 is added to the sensor data at the time of integration with light projection to perform offset correction.

Next, in step S126, the corrected data is stored in the RAM in the CPU 105.

Next, in step S127, sensor data at the time of integration with light projection for performing offset correction is set.

Next, in step S128, sensor data at the time of integration without light projection used for offset correction is set.

Next, in step S129, it is determined whether or not correction has been completed for all of the sensor data for which offset correction is to be performed.
0, and if not completed, the process returns to step S124.

Next, in step S130, it is determined whether the correction has been completed for both sensor data of the pair of line sensors 102a and 102b, and if both have been completed, the process returns. If not completed, the process returns to step S1.
Return to 22.

FIG. 8 shows a first embodiment of FIG.
9 is a flowchart showing a procedure when offset correction is performed simultaneously with reading of sensor data during integration without light projection in step S107 shown in FIG.

First, in step S131, the number of sensor data to be subjected to offset correction is set.

Next, in step S132, the head data of the data to be subjected to offset correction is set with the sensor data at the time of integration with light projection.

Next, in step S133, the A / D conversion circuit 104 performs A / D conversion and reads out the head data of the data used for offset correction in the sensor data at the time of integration without light projection.

Next, in step S134, the difference between the reference data and the sensor data at the time of integration without light projection is calculated to calculate an offset.

Here, the MAX value of the 8-bit A / D is 2
Although 55 is used as the reference data, a reference voltage level or the like at the time of integration may be used as the reference data.

Next, in step S135, the offset calculated in step S134 is added to the sensor data at the time of integration with light projection to perform offset correction.

Next, in step S136, the corrected data is stored in the RAM in the CPU 105.

Next, in step S137, sensor data at the time of integration with light projection for performing offset correction is set.

Next, in step S138, the sensor data at the time of integration without light projection used for the offset correction is A /
A / D conversion is performed by the D conversion circuit 104 and read.

Next, in step S139, it is determined whether or not the correction has been completed for all of the sensor data for which offset correction is to be performed.
0, and if not completed, the process returns to step S134.

Next, in step S140, it is determined whether the correction has been completed for both sensor data of the pair of line sensors 102a and 102b, and if both have been completed, the process returns. If not completed, the process returns to step S1.
Return to 32.

(Second Embodiment) The configuration of a distance measuring device for a camera according to the second embodiment is the same as that of the first embodiment shown in FIG.
This is the same as the configuration of the distance measuring device of the camera according to the embodiment.

That is, in the above-described first embodiment, the offset correction is performed by the same number of times as the number of times of the active mode integration with the signal light projection, based on the result of the integration operation in the active mode without the light projection. In contrast to this, in the second embodiment, the number of integration operations in the active mode without light emission is set to half of the number of light emission in the active mode integration with light emission, and the offset is set. The offset is detected and corrected based on the offset.

However, the number of integration operations in the active mode without light emission is not limited to half of the number of light emission times in active mode integration with light emission, but may be 1/3 or 1/4.

According to the second embodiment, the distance measurement time can be reduced as compared with the first embodiment, and high-speed and high-accuracy distance measurement can be performed.

FIG. 9 is a flowchart showing a procedure of a distance measuring sequence according to the second embodiment.

First, in step S201, pre-ranging is performed in the active mode or the passive mode, and a ranging method is selected based on the result.

At this time, a distance measuring method may be selected by judging luminance using photometric data or the like.

Next, in step S202, step S
If the selection result at step 201 is the active mode, the process proceeds to step S203, and if the result is the passive mode, the process proceeds to step S203.
Proceed to 210.

Next, in step S203, an integration mode, a monitor range, a sensor sensitivity, an integration end condition, and the like are set.

Next, in step S204, the light emitting means 1
The active mode integration is performed while projecting the signal light from 07.

Next, in step S205, A / D conversion is performed by the A / D conversion circuit 104 to read out sensor data, and the data is stored in the RAM in the CPU 105.

Next, in step S206, step S206
The integration conditions are set in the same manner as 203.

Next, in step S207, the active mode integration is performed for half the number of cycles of the light emission in the integration in step S204 without projecting the signal light.

Next, in step S208, step S
The sensor data is read out in the same manner as
The data is stored in the RAM inside.

Next, in step S209, step S
Offset correction is performed based on the sensor data read in 208.

This offset correction is performed in step S208.
May be performed each time one data is read during the reading of the sensor data.

Next, in step S210, step S210
The integration conditions are set in the same manner as 203.

Next, in step S211, passive mode integration is performed.

Next, in step S212, step S212
The sensor data is read out in the same manner as
The data is stored in the RAM inside.

Next, in step S213, distance measurement data is calculated by a known correlation operation, interpolation operation, or the like.

FIG. 10 is a flowchart showing the procedure of offset correction according to the second embodiment.

First, in step S221, the number of sensor data to be subjected to offset correction is set.

Next, in step S222, the head data of the data to be subjected to offset correction is set with the sensor data at the time of integration with light projection.

Next, in step S223, head data of data used for offset correction is set in sensor data at the time of integration without light projection.

Next, in step S224, an offset is calculated by taking the difference between the reference data and the sensor data at the time of integration without light projection.

Here, the MAX value of the 8-bit A / D is 2
Although 55 is used as the reference data, a reference voltage level or the like at the time of integration may be used as the reference data.

Next, in step S225, the offset calculated in step S224 is doubled and added to the sensor data at the time of integration with light projection to perform offset correction.

Next, in step S226, the corrected data is stored in the RAM in the CPU 105.

Next, in step S227, sensor data at the time of integration with light projection for performing offset correction is set.

Next, in step S228, sensor data at the time of integration without light projection used for offset correction is set.

Next, in step S229, it is determined whether or not the correction has been completed for all of the sensor data for which offset correction is to be performed.
0, and if not finished, the process returns to step S224.

Next, in step S230, it is determined whether or not the correction has been completed for both sensor data of the pair of line sensors 102a and 102b. If both have been completed, the process returns. If not, the process returns to step S2.
Return to 22.

(Third Embodiment) The configuration of a distance measuring apparatus for a camera according to the third embodiment is similar to that of the first embodiment shown in FIG.
This is the same as the configuration of the distance measuring device of the camera according to the embodiment.

That is, in the above-described second embodiment, the offset is detected by setting the number of times of integration in the active mode without light projection to half of the number of times of light emission in the active mode integration with light projection. In contrast, in the third embodiment, the offset is first detected by performing one integration operation in the active mode without light projection, and then the light emission is performed. An active mode integration is performed, and correction is performed based on the detected offset due to one integration operation.

According to the third embodiment, the distance measuring time can be further reduced than in the second embodiment,
High-speed and high-accuracy ranging can be performed.

FIG. 11 is a flowchart showing a procedure of a distance measuring sequence according to the third embodiment.

First, in step S301, pre-ranging is performed in the active mode or the passive mode, and a ranging method is selected based on the result.

At this time, the distance measuring method may be selected by judging the luminance using the photometric data or the like.

Next, in step S302, step S
If the selection result at step 301 is the active mode, the process proceeds to step S303.
Go to 10.

Next, in step S303, an integration mode, a monitor range, a sensor sensitivity, an integration termination condition, and the like are set.

Next, in step S304, one cycle of active mode integration is performed without projecting the signal light.

Next, in step S305, A / D conversion is performed by the A / D conversion circuit 104 to read out sensor data, and the data is stored in the RAM in the CPU 105.

Next, in step S306, step S306
The integration condition is set in the same manner as in 303.

Next, in step S307, the light emitting means 1
The active mode integration is performed while projecting the signal light from 07.

Next, at step S308, at step S308
The sensor data is read out in the same manner as
The data is stored in the RAM inside.

Next, in step S309, step S309
Offset correction is performed based on the sensor data read in 305.

This offset correction is performed in step S308.
May be performed each time one data is read during the reading of the sensor data.

Next, in step S310, step S310
The integration condition is set in the same manner as in 303.

Next, in step S311, passive mode integration is performed.

Next, in step S312, step S3
The sensor data is read out in the same manner as
The data is stored in the RAM inside.

Next, in step S313, distance measurement data is calculated by a known correlation operation, interpolation operation, or the like.

FIG. 12 is a flowchart showing a procedure of offset correction according to the third embodiment.

First, in step S321, the number of sensor data to be subjected to offset correction is set.

Next, in step S322, the head data of the data to be subjected to offset correction is set with the sensor data at the time of integration with light projection.

Next, in step S323, head data of data used for offset correction is set in sensor data at the time of integration without light projection.

Next, in step S324, an offset is calculated by taking the difference between the reference data and the sensor data at the time of integration without light projection.

Here, the MAX value of the 8-bit A / D is 2
Although 55 is used as the reference data, a reference voltage level or the like at the time of integration may be used as the reference data.

Next, in step S325, the offset calculated in step S324 is added to the sensor data at the time of integration with light projection multiplied by the number of times of light emission at the time of integration with light projection to add offset.

Next, in step S326, the corrected data is stored in the RAM in the CPU 105.

Next, in step S327, sensor data at the time of integration with light projection for performing offset correction is set.

Next, in step S328, sensor data at the time of integration without light projection used for offset correction is set.

Next, in step S329, it is determined whether or not correction has been completed for all of the sensor data for which offset correction is to be performed.
0, and if not completed, the process returns to step S324.

Next, in step S330, it is determined whether the correction has been completed for both sensor data of the pair of line sensors 102a and 102b, and if both have been completed, the process returns. If not completed, the process returns to step S3.
Return to 22.

(Fourth Embodiment) The configuration of a distance measuring apparatus for a camera according to the fourth embodiment is similar to that of the first embodiment shown in FIG.
This is the same as the configuration of the distance measuring device of the camera according to the embodiment.

That is, in the fourth embodiment, active mode integration with light emission is performed with a high sensor sensitivity in order to enhance the signal light detection capability. However, when an offset is detected, random noise or the like is detected. In order to prevent the offset detection accuracy from deteriorating due to the influence, the sensor sensitivity is set low and the integration in the active mode without light projection is performed.

Then, according to the fourth embodiment,
Even more accurate distance measurement can be performed.

FIG. 13 is a flowchart showing a procedure of a distance measuring sequence according to the fourth embodiment.

First, in step S401, pre-ranging is performed in the active mode or the passive mode, and a ranging method is selected based on the result.

At this time, the distance measuring method may be selected by judging luminance using photometric data or the like.

Next, in step S402, step S
If the selection result at step 401 is the active mode, the process proceeds to step S403. If the selection result is the passive mode, the process proceeds to step S403.
Proceed to 410.

Next, in step S403, an integration mode, a monitor range, a sensor sensitivity, an integration end condition, and the like are set.

Here, the sensor sensitivity is set to a high sensitivity.

Next, in step S404, the light emitting means 1
From 07, active mode integration is performed with high sensitivity while projecting signal light.

Next, in step S405, A / D conversion is performed by the A / D conversion circuit 104 to read out sensor data, and the data is stored in the RAM in the CPU 105.

Next, in step S406, step S406
The integration conditions are set in the same manner as in 403.

Here, the sensor sensitivity is set to low sensitivity.

Next, in step S407, the active mode integration is performed with the sensor sensitivity set to be low for the same number of cycles as the number of projections in the integration in step S404 without projecting the signal light.

Next, in step S408, step S408
The sensor data is read out in the same manner as
The data is stored in the RAM inside.

Next, in step S409, step S
Offset correction is performed based on the sensor data read in 408.

This offset correction is performed in step S408.
May be performed each time one data is read during the reading of the sensor data.

Next, in step S410, step S
The integration conditions are set in the same manner as in 403.

Next, in step S411, passive mode integration is performed.

Next, in step S412, step S412
The sensor data is read out in the same manner as
The data is stored in the RAM inside.

Next, in step S413, distance measurement data is calculated by a known correlation operation, interpolation operation, or the like.

FIG. 14 is a flowchart showing the procedure of offset correction according to the fourth embodiment.

First, in step S421, the number of sensor data to be subjected to offset correction is set.

Next, in step S422, the head data of the data to be subjected to offset correction is set with the sensor data at the time of integration with light projection.

Next, in step S423, head data of data used for offset correction is set in sensor data at the time of integration without light projection.

Next, in step S424, an offset is calculated by taking the difference between the reference data and the sensor data at the time of integration without light projection.

Here, the MAX value of the 8-bit A / D 2
Although 55 is used as the reference data, a reference voltage level or the like at the time of integration may be used as the reference data.

Next, at step S425, the sensor data at the time of integration with light projection is added to the offset calculated at step S424 by multiplying the offset by a sensitivity coefficient for correcting an offset error due to a difference in sensor sensitivity, thereby performing offset correction. .

Next, in step S426, the corrected data is stored in the RAM in the CPU 105.

Next, in step S427, sensor data at the time of integration with light projection for performing offset correction is set.

Next, in step S428, sensor data at the time of integration without light projection used for offset correction is set.

Next, in step S429, it is determined whether or not correction has been completed for all of the sensor data for which offset correction is to be performed.
0, and if not completed, the process returns to step S424.

Next, in step S430, it is determined whether correction has been completed for both sensor data of the pair of line sensors 102a and 102b, and if both have been completed, the process returns.
Return to 22.

(Fifth Embodiment) The configuration of a camera distance measuring apparatus according to the fifth embodiment is similar to that of the first embodiment shown in FIG.
This is the same as the configuration of the distance measuring device of the camera according to the embodiment.

In other words, in the fifth embodiment, the integration time in the active mode without signal light emission for offset detection is shorter than the integration time in the active mode with light emission.

The fifth embodiment is effective when the main factor of the occurrence of the offset is a switching operation in the steady light removing circuit and the integrating circuit.

According to the fifth embodiment, the distance measurement time can be further reduced, and high-speed and high-accuracy distance measurement can be performed.

FIG. 15 is a timing chart showing a sequence of integration and reading of sensor data in the fifth embodiment.

That is, FIG. 15A shows the integration start control signal RESET, and the integration starts when L → H.

FIG. 15B shows an integration stop control signal EXTEND, and integration stops when H → L.

FIG. 15C shows the active mode integration control signal INTCLK, and the period between the first pulse, the second pulse, and the third pulse is T3 in FIG.
The period between the third pulse and the fourth pulse corresponds to T5 in FIG. 3, respectively, and thereafter, it is repeated.

FIG. 15D shows the signal light projection in which the signal light is projected in the H period.

FIG. 15E shows the sensor data read control signal RWCLK, which outputs the integrated data of each photodiode for each pulse.

FIG. 4F shows the integrated data output MDATA of the monitor sensor.

This monitor sensor is, for example, a sensor having the highest integration speed among the photodiodes constituting the line sensors 102a and 102b.

In FIG. 15, t1 is an active mode integration period with light emission, and integration operations of 1 to n cycles are performed until the MDATA output reaches a predetermined level.

Further, t2 is a sensor data reading period in active mode integration with light projection.

Further, t3 is an active mode integration period without light emission, in which the integration operation of n cycles performed in active mode integration with light emission is performed without light emission.

However, the time of one cycle of the integration operation is set to a time shorter than that in the active mode integration with light emission.

Further, t4 is a sensor data reading period in active mode integration without light projection.

(Sixth Embodiment) The configuration of a camera distance measuring apparatus according to the sixth embodiment is similar to that of the first embodiment shown in FIG.
This is the same as the configuration of the distance measuring device of the camera according to the embodiment.

That is, the sixth embodiment is similar to the third embodiment.
In the modification of the third embodiment, one integration operation in the active mode without signal light projection for detecting an offset is executed at the beginning of the distance measurement sequence.

FIG. 16 is a flowchart showing a procedure of a distance measuring sequence according to the sixth embodiment.

First, in step S601, an integration mode, a monitor range, a sensor sensitivity, an integration termination condition, and the like are set.

Next, in step S602, one cycle of active mode integration is performed without projecting signal light.

Next, in step S603, A / D conversion is performed by the A / D conversion circuit 104 to read out sensor data, and the data is stored in the RAM in the CPU 105.

Next, in step S604, pre-ranging is performed in the active mode or the passive mode, and a ranging method is selected based on the result.

At this time, a distance measurement method may be selected by judging luminance using photometric data or the like.

Next, in step S605, step S605
If the selection result in step 604 is the active mode, the process proceeds to step S606, and if the selection result is the passive mode, the process proceeds to step S606.
Proceed to 610.

Next, in step S606, step S606
The integration conditions are set in the same manner as in 601.

Next, in step S607, the light emitting means 1
The active mode integration is performed while projecting the signal light from 07.

Next, in step S608, step S608
The sensor data is read out in the same manner as
The data is stored in the RAM inside.

Next, in step S609, step 6
Offset correction is performed based on the sensor data read in step 08.

This offset correction is performed in step S608.
May be performed each time one data is read during the reading of the sensor data.

Next, at step S610, step S610
The integration conditions are set in the same manner as in 601.

Next, in step S611, passive mode integration is performed.

Next, in step S612, step S612
The sensor data is read out in the same manner as
The data is stored in the RAM inside.

Next, in step S613, distance measurement data is calculated by a known correlation operation, interpolation operation, or the like.

(Seventh Embodiment) The configuration of a camera distance measuring apparatus according to the seventh embodiment is similar to that of the first embodiment shown in FIG.
This is the same as the configuration of the distance measuring device of the camera according to the embodiment.

In the seventh embodiment, one integration operation in the active mode without signal light projection for detecting an offset is performed when the power switch of the camera is turned on and when the camera is on standby. It is designed to be executed when in the state.

According to the seventh embodiment, the case where the offset detection is performed in the distance measurement sequence is as follows.
Further, the distance measurement time can be shortened, and high-speed and high-accuracy distance measurement can be performed.

FIG. 17 is a flowchart showing the sequence of a camera sequence according to the seventh embodiment.

First, in step S701, the state of the camera such as the opening of the lens barrier of the camera and the setup of the lens frame is initialized.

Next, in step S702, data such as adjustment values are read out from a non-volatile memory such as an EEPROM (not shown) and expanded in the RAM of the CPU 105.

Next, in step S703, an integration mode, a monitor range, a sensor sensitivity, an integration termination condition, and the like are set.

Next, in step S704, one cycle of active mode integration is performed without projecting signal light.

Next, in step S705, A / D conversion is performed by the A / D conversion circuit 104 to read out sensor data, and RAM data in the CPU 105 is stored.

Next, in a step S706, it is determined whether or not the first release button of the camera is pressed.
If it has been pressed, the process proceeds to step S711, and if it has not been pressed, the process proceeds to step S707.

Next, in step S707, step S707
The integration conditions are set in the same manner as in step 703.

Next, in step S708, step S708
As in 704, one cycle of active mode integration is performed without projecting signal light.

Next, at step S709, step S709
The sensor data is read out in the same way as
The data is stored in the RAM inside.

Next, in step S710, it is determined whether or not the power switch of the camera has been turned off. If the power switch has been turned off, the camera sequence ends, and if it has been turned on, the process returns to step S706.

Next, in step S711, photometric data for performing exposure control during photographing is measured.

Next, in step S712, subject distance data used for drive control of the focus adjusting lens is measured.

At this time, offset correction is performed using the sensor data read in step S705 or step 709.

Next, in step S713, step S713
The extension amount of the focus adjusting lens is calculated from the subject distance data measured in 712.

Next, in step S714, step S714
As in step 706, it is determined whether or not the first release button of Kamefu has been pressed.
The process proceeds to 715, and if not pressed, returns to step S706.

Next, in step S715, it is determined whether or not the second release button of the camera has been pressed. If the second release button has been pressed, the process returns to step S716. If not, the process returns to step S714. Next, step S716
Then, the focus adjustment lens is driven based on the amount of extension determined in step S713. Next, in step S71.
In step 7, the film surface is exposed based on the photometric data obtained in step S711.

Next, in step S718, step S718
The film exposed at 717 is wound up, and step S
Return to 706.

(Eighth Embodiment) FIG. 18 is a block diagram showing a configuration of a camera distance measuring apparatus according to an eighth embodiment.

In FIG. 18, reference numerals 801a and 801a
Reference numeral 1b denotes a light receiving lens for forming a subject image on the area sensors 802a and 802b.
a and 802b photoelectrically convert the subject image formed by the light receiving lenses 801a and 801b in accordance with the light intensity thereof;
It is a pair of area sensors that convert to electric signals.

Also, in FIG.
Is an integration control circuit that controls the integration operation of the pair of area sensors 802a and 802b and outputs a subject image signal as the integration result. Reference numeral 804 denotes an integration control circuit 803.
A / D for reading the subject image signal and performing A / D conversion
It is a conversion circuit.

Also, in FIG.
Is a CPU for outputting various control signals, inputting various data, calculating distances, and the like. Reference numeral 806 removes a stationary photocurrent component from the photocurrent output from the pair of area sensors 802a and 802b. This is a stationary light removal circuit.

Further, in FIG. 18, reference numeral 807
Is a pair of area sensors 802 for distance measurement toward a subject.
a light projecting means for projecting the distance measuring light (signal light) a and 802 b, and is controlled by the CPU 805.

The camera distance measuring apparatus according to the eighth embodiment has a pair of area sensors instead of the pair of line sensors 102a and 102b of the camera distance measuring apparatus according to the first embodiment shown in FIG. The same applies except that 802a and 802b are used.

That is, in the eighth embodiment, a pair of area sensors 802a and 802b are used as light receiving elements in order to two-dimensionally measure the distance in a photographing screen.

According to the eighth embodiment,
By using the pair of area sensors 802a and 802b, it is possible to two-dimensionally measure the distance in the shooting screen, so that more sophisticated distance measurement can be performed.

As described above, according to the camera distance measuring apparatus of the present invention, when active mode integration is performed in a hybrid type distance measuring apparatus without using a large-capacity non-volatile memory, light is not received. Since the offset generated in each sensor constituting the element can be corrected, a highly accurate distance measurement can be performed with an inexpensive and small configuration.

The present invention relates to a hybrid type AF
However, the present invention can be applied to an active AF in which the light receiving side is a sensor array.

In the present specification described in the above-described embodiments, in addition to claims 1 to 3 described in the claims, the inventions shown below as supplementary notes 1 to 10 are described. include.

(Supplementary Note 1) Light projecting means for projecting signal light toward a subject, a light receiving lens for forming a pair of subject images on a pair of line sensors, and a pair of light beams formed by the light receiving lens A pair of line sensors for converting a subject image into an electric signal according to the light intensity; an integral control means for performing integral control on the pair of line sensors; and removing a light component constantly incident on the pair of line sensors. Stationary light removing means, reading means for reading the subject image data output from the pair of line sensors, and calculation for calculating data according to the subject distance based on the subject image data read by the reading means Means, projecting signal light from the light projecting means toward the subject, removing the steady light component from the subject by the steady light removing means, A camera capable of executing two integration modes, an active mode integration that repeats the integration operation of integrating only the signal light component from the subject a plurality of times and a passive mode integration that integrates the steady light component from the subject. In the distance device, when signal light is projected by subject image data output from the pair of line sensors when performing active mode integration when signal light is not projected toward the subject from the light projecting means. Wherein the subject image data output from the pair of line sensors is corrected when the active mode integration is performed.

(Supplementary Note 2) The number of repetitions of the active mode integration operation when the signal light is projected from the light projecting unit toward the subject and the active mode integration operation when the same number of signal lights are not projected are performed. The subject image data output from the pair of line sensors obtained when the signal light is projected is corrected based on the subject image data output from the pair of line sensors obtained as described above. 3. The distance measuring device according to 1.

(Supplementary Note 3) An integration operation in which the signal light is not projected a smaller number of times than the active integration operation in the case where the signal light is projected is performed. 2. The distance measuring apparatus according to claim 1, wherein the processing is performed in accordance with the ratio, and the sensor data when the signal light is projected is corrected.

(Supplementary Note 4) The active integration operation in the case where the signal light is not projected is performed with a fixed number of repetitions, and the sensor data obtained thereby is calculated by comparing the ratio of the sensor data with the number of times the integration operation is repeated in the case where the signal light is projected. 2. The distance measuring apparatus according to claim 1, wherein the sensor data is processed according to the correction, and the sensor data when the signal light is projected is corrected.

(Supplementary Note 5) Active mode when signal light is projected from the light projecting means toward the subject Active mode when signal light is not projected in a shorter time than one integration time during the integration operation The subject image data output from the pair of line sensors obtained when the signal light is projected is corrected based on the subject image data output from the pair of line sensors obtained by performing the integration operation. 2. The distance measuring device according to claim 1, wherein

(Supplementary Note 6) A case where the signal light is not projected with a lower sensitivity than the sensitivity of the pair of line sensors during the active mode integration operation when the signal light is projected from the light projecting means toward the subject. The subject image data output from the pair of line sensors obtained when the signal light is projected is corrected based on the subject image data output from the pair of line sensors obtained by performing the active mode integration operation. 3. The distance measuring device according to claim 1, wherein

(Supplementary note 7) The distance measurement according to Supplementary note 1, wherein after the active integration operation when the signal light is projected, the integration operation when the signal light is not projected is performed to correct the sensor data. apparatus.

(Supplementary Note 8) An additional operation characterized in that an integration operation when no signal light is projected is performed before the distance measurement is started, and the sensor data when the signal light is projected is corrected based on the sensor data at that time. 2. The distance measuring device according to 1.

(Supplementary Note 9) Before the active integration operation when projecting the signal light, the integration operation when the signal light is not projected is performed to correct the sensor data. Distance device.

(Supplementary Note 10) An additional operation characterized in that an integration operation is performed when no signal light is projected when the power of the camera is turned on, and the sensor data when the signal light is projected is corrected based on the sensor data at that time. 2. The distance measuring device according to 1.

[0274]

Therefore, as described above, according to the present invention, in a hybrid type distance measuring apparatus, when active mode integration is performed without using a large-capacity nonvolatile memory, a light receiving element is used. It is possible to provide a distance measuring device capable of correcting an offset generated in each of the constituent sensors and performing highly accurate distance measurement.

[Brief description of the drawings]

FIG. 1 is a block diagram of a main part showing a configuration of a camera distance measuring apparatus according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating a specific configuration of a stationary light removing circuit in FIG. 1;

FIG. 3 is a timing chart shown to explain a basic operation of the steady light removing circuit of FIG. 1;

FIG. 4 is a timing chart showing a sequence of integration and reading of sensor data according to the first embodiment;

FIG. 5 is a diagram showing sensor data in each active mode integration according to the first embodiment.

FIG. 6 is a flowchart illustrating a procedure of a distance measurement sequence according to the first embodiment;

FIG. 7 is a flowchart illustrating a procedure of offset correction according to the first embodiment;

FIG. 8 is a flowchart illustrating a procedure in the first embodiment when offset correction is performed simultaneously with reading of sensor data during integration without light projection in step S107 shown in FIG. 6;

FIG. 9 is a flowchart illustrating a procedure of a distance measurement sequence according to the second embodiment of the present invention.

FIG. 10 is a flowchart illustrating a procedure of offset correction according to the second embodiment;

FIG. 11 is a flowchart illustrating a procedure of a distance measurement sequence according to the third embodiment of the present invention.

FIG. 12 is a flowchart illustrating a procedure of offset correction according to the third embodiment;

FIG. 13 is a flowchart illustrating a procedure of a distance measurement sequence according to the fourth embodiment of the present invention.

FIG. 14 is a flowchart illustrating a procedure of offset correction according to a fourth embodiment;

FIG. 15 is a timing chart showing a sequence of integration and reading of sensor data according to a fifth embodiment of the present invention.

FIG. 16 is a flowchart illustrating a procedure of a distance measurement sequence according to the sixth embodiment of the present invention.

FIG. 17 is a flowchart showing a camera sequence procedure according to the seventh embodiment of the present invention.

FIG. 18 is a block diagram showing a configuration of a camera distance measuring apparatus according to an eighth embodiment of the present invention.

[Explanation of symbols]

101a, 101b: light receiving lens, 102a, 102b: pair of line sensors, 103: integration control circuit as integration control means, 104: analog / digital (A / D) conversion circuit, 105: CPU, 106: stationary light removal means 107: Light emitting means, 110: Photodiode, 111: Transfer transistor, SW1, SW2, SW3: Switch, 112: Inverting amplifier, C1, C2, C3, C4: Capacitance element, 113: inverting amplifier, VS1 ... input of the inverting amplifier circuit, VS2 ... output of the inverting amplifier circuit, photocurrent corresponding to the I _PD ... stationary light, [Delta] I _PD ... error component, I _PDS ... signal light component, RESET ... integration start control signal, EXTEND: integration stop control signal, INTCLK: active mode integration control signal, RWCLK: sensor data Readout control signal, MDATA ... Integrated data output of monitor sensor, 801a, 801b ... Light receiving lens, 802a, 802b ... A pair of area sensors, 803 ... Integration control circuit, 804 ... Analog / digital (A / D) conversion circuit, 805 ... CPU, 806: steady light removing circuit, 807: light emitting means.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G03B 13/36 G03B 3/00 A F term (Reference) 2F112 AA08 AA09 BA07 BA10 CA02 DA05 EA05 FA03 FA07 FA21 FA25 FA29 FA45 2H011 AA01 BA05 BA14 BB04 BB05 CA28 2H051 BB07 BB20 CB20 CD01 CE06 CE08 CE21 DA02 DA11 GB12 5J084 AA05 AB07 AC08 AD07 BA39 BB01 CA44 CA49 EA04 EA11

Claims (6)

[Claims] 1. A light projecting means for projecting light for distance measurement to a subject, a light receiving means comprising a plurality of sensors for receiving reflected signal light of the light for distance measurement from the subject, Storage means for storing output data from a plurality of sensors of the light receiving means in a non-light emitting state, wherein a plurality of the light receiving means in the non-light emitting state of the distance measuring light stored in the storage means are provided. A distance measuring device for correcting output data from a plurality of sensors of the light receiving means in a light projection state of the distance measuring light based on output data from the sensor. 2. An integral control means for performing integral control on a plurality of sensors of the light receiving means, a steady light removing means for removing light components constantly incident on the plurality of sensors of the light receiving means, A reading unit that reads subject image data output from the plurality of sensors; and a computing unit that computes data corresponding to a subject distance based on the subject image data read by the reading unit. Projecting the distance-measuring light from the light projecting means toward the subject, removing the steady light component from the subject by the steady light removing means, and measuring the distance from the subject by the integration control means. Active mode integration in which the integration operation for integrating only the light component is repeated a plurality of times, and passive mode integration in which the steady light component from the subject is integrated Distance measuring apparatus according to claim 1, characterized in that a viable two integration modes. 3. In the non-light emitting state of the distance measuring light, the distance measuring light is obtained by subject image data output from a plurality of sensors of the light receiving means when the integration control means performs active mode integration. 3. An object image data output from a plurality of sensors of said light receiving means when active mode integration is performed by said integration control means in a light projection state.
3. The distance measuring device according to 1. 4. In the projection state of the distance measuring light, the non-projection of the distance measuring light is the same as the number of repetitions of the active mode integration operation when the integration control means performs the active mode integration. In the light state, a plurality of the light receiving means obtained in the light emitting state of the distance measuring light by subject image data from a plurality of sensors of the light receiving means obtained by performing an active mode integration operation by the integration control means. 3. The distance measuring apparatus according to claim 2, wherein subject image data from said sensor is corrected. 5. In the projection state of the distance measurement light, the distance measurement is performed in a time shorter than one integration time during an active mode integration operation when the integration control means performs the active mode integration. In the light non-projecting state, the subject obtained in the projecting state of the distance measuring light by subject image data from a plurality of sensors of the light receiving unit obtained by performing an active mode integration operation by the integration control unit. 3. The distance measuring apparatus according to claim 2, wherein subject image data from a plurality of sensors of the light receiving means is corrected. 6. In the projection state of the distance-measuring light, the sensitivity of the plurality of sensors of the light receiving unit is lower than that of the plurality of sensors in active mode integration operation when active mode integration is performed by the integration control unit. In the non-projection state of the distance-measuring light, the projection state of the distance-measuring light is determined by subject image data from a plurality of sensors of the light-receiving means obtained by performing an active mode integration operation by the integration control means. 3. The distance measuring apparatus according to claim 2, wherein the object image data obtained from the plurality of sensors of the light receiving means obtained in step (c) is corrected.